SNX-111 (IND#45718) is a voltage-sensitive calcium channel blocker that specifically blocks neuronal (N-type) calcium channels. These channels are found in highest density within the substantia gelatinosa of the dorsal horn, where blockade of calcium influx has been shown to create analgesia. The present study is designed to assess the safety and feasibility of intrathecal SNX-111 in relieving chronic, nonmalignant pain. Drug will be delivered via temp.intrathecal catheter/external pump or, in patients with previous device.